llvm-cov-html-diff

This tool allows you to inspect and debug fuzzbench results to know why one fuzzer is better than the other.

• Enable the generation of llvm-cov coverage report.
• Use this tool to diff the report.
• Check the report: Check those lines that is not covered by one fuzzer but covered by the other.

Usage

1. Install the tool: pip install llvmcovdiff
2. Use the tool.

python -m llvmcovdiff <old_report_folder> <new_report_folder> <output_report_folder>

For example, for a fuzzbench result:

python -m llvmcovdiff ./2024-05-13-new-cov/coverage/reports/proj4_proj_crs_to_crs_fuzzer/aflplusplus/ ./2024-05-13-new-cov/coverage/reports/proj4_proj_crs_to_crs_fuzzer/afl/ out3

Develop

python3 -m build && python3 -m pip install ./dist/llvmcovdiff-0.0.4.tar.gz

Details

In generated report from llvm-cov

• There are index.html that shows the main status of the coverage.
• There are xxxx.c.html or xxx.h.html that shows line coverage.

Given two llvm-cov report folder, We generate a new folder that shows the differences.

FAQ

1. Why some line hit count changed but not highlighted?

For line coverage count, we only highlight those counts that goes from zero to non-zero, or from non-zero to zero.

Others

Thanks to https://github.com/Dentosal/llvm-codecov-diff/blob/0352d07e486f75b2dfb8bf2d7eb8a6e948e19106/app.py

Tested on python 3.10 pip 24.2:

beautifulsoup4==4.12.2